Google announced a new and improved experience when you access Gmail and Calendar through the browser of your iPhone and Android-powered devices. Here is more details on these new improvements from Google team:

"What's new? For Gmail, we've improved the user interface to make it easier to message on the go, and we've introduced "Floaty Bar," which makes sure common actions such as archive and delete are only a click away (check out the video tour below). You can also start the application, compose mail, and open recently read messages even when you're offline. With the new Calendar, you can edit or respond to an event and, like Gmail, the app is accessible even without a network connection. To quickly navigate between Gmail, Calendar, and other mobile applications, you can use the classic links that now always appear across the top of the screen. The "more" menu provides easy access to the full list of applications. To read more about what's new, take a look at the Gmail and Calendar posts on the Mobile blog.

So you may be asking, "Why web apps?" Well, from a product perspective, web apps allow us to iterate quickly, so users benefit because they will see new features appear in the browser without having to download anything. We can experiment rapidly by learning how people use the features and then choose whether to invest further in that direction or move on. Using the browser as a delivery platform also means that users will see new feature releases happening more frequently because we can maximize our engineering efficiency by sharing code across device families. Looking at this release of Gmail, there is 90%+ code share between the Android and iPhone experience. As new devices come on the market with high-end browsers, most of the work is already done. (Hint to OEMs: you provide a world-class browser, we'll make sure Gmail and Calendar for mobile works on your platform.)

To give it a try, visit gmail.com in your mobile browser. To access Calendar, click on the Calendar link at the top of the Gmail page. To make it easy to access Gmail and Calendar, we recommend creating a home screen link. Please note, these web-based mobile products are only available on iPhone OS 2.2.1 or higher and on all Android-powered devices."